Field deployable system to measure clumped isotopes

A method for enhancing hydrocarbon production comprising:

• providing a field deployable system in fluid communication with a subsurface formation, wherein the field deployable system comprises mass spectrometric instrumentation that is in fluid communication with drilling equipment or attached to pipelines flowing produced fluids, and wherein the field deployable system is configured to measure a position specific isotope signature of a hydrocarbon compound, wherein the position specific isotope signature provides an indication of a concentration of at least one structurally distinct isotopologue of the hydrocarbon compound that contains at least one rare isotope;
• providing a mud sampling system in fluid communication with the subsurface formation;
• obtaining a plurality of mud gas samples from the mud sampling system and analyzing the mud gas samples to determine whether there the variation in signatures of the mud gas samples exceeds a predetermined threshold;
• when the variation in the signatures of the mud gas samples exceeds the predetermined threshold, obtaining one or more hydrocarbon samples from the subsurface formation at a first time and analyzing each of the hydrocarbon samples with the field deployable system to determine a baseline position specific isotope signature, wherein the hydrocarbon sample is a mud gas sample or a produced gas sample;
• when the variation in the signatures of the mud gas samples exceeds the predetermined threshold, obtaining one or more hydrocarbon sample from the subsurface formation at a second time, wherein the second time is after the first time, and analyzing each of the hydrocarbon samples with the field deployable system to determine a monitored position specific isotope signature, wherein the hydrocarbon sample is a mud gas sample or a produced gas sample;
• comparing the monitored position specific isotope signature with the baseline position specific isotope signature;
• hydraulic fracturing of a wellbore in the subsurface formation or adjusting an injection of gas or liquid into the subsurface formation based on the comparison;
• and
• producing hydrocarbons from the subsurface.